Analyze the sudden failure influence to urban rail transit normal operation, has important significance to grasp the key of failure emergency treatment. This paper take moving block mode for example, first by use of multi-particle traction model, general consider the passenger comfort, safety control and other factors, design the multi-train tracking calculate model. Then according to the different influence to urban rail transit operation, classify the sudden failure into two kinds: sudden train failure and sudden section break off failure, analyze the multi-train movement simulate arithmetic under the two kinds of failure, based on this, design the simulation system’s workflow, build the urban rail transit multi-train movement simulate system under sudden failure. Finally, by analyze the calculate results of two kinds of failure, verified the system’s validity. Simulate urban rail transit multi-train movement process under sudden failure can master the detail instance about failure influence operation, deeply analysis the infect’s diffusion process caused by failure or delay, provide a powerful assist analyze tool to analysis the network’s operation reliability, constitute correlative emergency plan.